Zudwig weber



Patented Aug. 30,1932

OFFICE;

LUDWIGWEBER, 0F BERLIN-WILMERSDORF, GERMANY rnocnss ron 'rnn rnonncrron or SEMICOKE nnreun'rzrns FROM BIrUMInouscoAL No Drawing. Application filed October 13, 1927, Serial No. 226,049, and in Germany October 14,1926. 7

The low temperature coking or distillation of bituminous fuels is known, and that it is advantageous in certain cases to briquette the fuelbefore distillation is also known. The invention described in the following-is not concerned with the low temperature dis tillation of lignite, peat and the' like, the briquetting of which involves quite different considerations than for example bituminous coal. The invention is only concerned with the latter. I

In the low temperature distillation of ordinary coal it has, as was to be expected, been found that only lumpy material was most suitable for the distillation. Commercially however,the distillation of lumpy material is of noconsequence because the lumps always find amarket at a good price. On this account it is only the. bituminous fine coal which comes under consideration for distillation because there is not a suflicient outlet for this in the condition in which it occurs and consequently the price is low and the necessary economic circumstances exist.

Most of the distillation processeswhich have become known in practicefor ordinary coal, use the fine coal in the condition in which it occurs. As this fine coal lies very compact and coal in itself is a v'erypoor conductor of heat, mass should be often turned over during the heat treatment in order to "get an evenheating of the entire material.

The almost universal use of rotary tube furnaces for the low temperature distillation of ordinary coal comes about in this way. As a necessary consequence of the constant turning of the material a semi-coke principally in dust form'and a more or less considerably dusty tar are obtained. As these two products-semi-coke and primary low temperature tar-must carry the costs of the low temperature coal distillation, there is under these conditions no prospect for the distillation of fine coal in the loose dust form, so as to provide a useful solution to the pressing problem of mining and general industrial circles, namely, economic production of primary low temperature tar.

On this account it has also been proposed a it is desirable that the.

to briquette the bituminous fine coal first of all and then distill.

v I In carrying out the process according to the invention, pitch and similar organic binders are fundamentally avoided and replacedby such "binders which on heating not only do not soften but rather dry, set or otherwise harden. There are many such binders avail:

able. Y

We' will consider first of all the water soluble binders, such as sulphitespent liquors, further those known under the name inorganic binders or also emulsion like binding mixtures such as for example binders consisting of an aqueous mixture of sulphite spent liquor or cellulose pitch phite spent liquor) with clay in the finest state of subdivision so that it constitutes an emulsion or colloidal suspension, and when subsequently heated acts so as to form a skeleton, because the clay'dehydrates. and thus becomes hard and porous, whilst the sulphite spent liquor as adhesive medium dries and under continued heating carbonizes; In cases where it is important to avoid an increase of ash such as the clay would give, coke yielding organic materials as for example, fine coal dust can be suspended in the sulphite spent liquor. Instead ofthe sulphite spent liquor other adhesive media such as size (i. e. aqueous glue solution), water-glass or the like can be used. 7

Such binders have this in common, as already explained, that they require a subsequent heat treatment for drying or roasting of the briquettes. This is where the new invention applies. That is,'inorganic binders having refractory properties of clay in forming a hard briquette upon molding, pressing and heating to 800 to 1000 degrees C., such as lime, cement, magnesia, and similar materials may be employed.

Whilst choosing suitable binders the briquettes produced from bituminous coal are not only dried or roasted but the heat treatment which has normally been taken at most to a temperature of about 230 C. is raised to a temperature of 450 -500 O; according to what is most suitable for distillation under 4 the particular conditions, using a suitable 

